package com.said.today.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.said.today.dto.Result;
import com.said.today.dto.ScrollResult;
import com.said.today.dto.UserDTO;
import com.said.today.entity.Blog;
import com.said.today.entity.Follow;
import com.said.today.entity.User;
import com.said.today.mapper.BlogMapper;
import com.said.today.service.IBlogService;
import com.said.today.service.IFollowService;
import com.said.today.service.IUserService;
import com.said.today.utils.RedisConstants;
import com.said.today.utils.SystemConstants;
import com.said.today.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private IUserService userService;
    @Resource
    private IFollowService followService;
    @Override
    public Result queryHotBlog(Integer current) {
        // 根据用户查询
        Page<Blog> page = query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据
        List<Blog> records = page.getRecords();
        // 查询用户
        records.forEach(blog->{
            this.queryBlogUser(blog);
            this.isBlogLiked(blog);
        });
        return Result.ok(records);
    }

    @Override
    public Result queryBlogById(Long id) {
        // 1.查询blog
        Blog blog = getById(id);
        if(blog == null){
            return Result.fail("笔记不存在");
        }
        // 查询blog有关的用户
        queryBlogUser(blog);
        // 查询blog是否被点赞
        isBlogLiked(blog);
        return Result.ok(blog);
    }

    private void isBlogLiked(Blog blog) {
        // 1.获取登录用户
        UserDTO user = UserHolder.getUser();
        if(user == null){
            // 未登录用户，无需点赞查询
            return;
        }
        Long userId = UserHolder.getUser().getId();
        // 2.判断当前用户是否已经点赞
        String key = "blog:liked" + blog.getId();
        Double score = stringRedisTemplate.opsForZSet().score(key, String.valueOf(userId));
        blog.setIsLike(BooleanUtil.isTrue(score != null));
    }

    @Override
    public Result likeBlog(Long id) {
        // 1.获取登录用户
        Long userId = UserHolder.getUser().getId();
        // 2.判断当前用户是否已经点赞
        String key = RedisConstants.BLOG_LIKED_KEY + id;
        Double score = stringRedisTemplate.opsForZSet().score(key, String.valueOf(userId));
        if(score == null){
            // 3.如果未点赞，可以点赞
            // 3.1数据库点赞数+1
            boolean isSuccess = update().setSql("liked = liked +1").eq("id", id).update();
            if(isSuccess){
                // 3.2保存用户到redis的set集合 ZADD key Value score
                stringRedisTemplate.opsForZSet().add(key,String.valueOf(userId),System.currentTimeMillis());
            }
        } else {
            // 4.如果已经点赞，取消点赞
            // 4.1数据库点赞数-1
            boolean isSuccess = update().setSql("liked = liked -1").eq("id", id).update();
            if(isSuccess){
                // 3.2把用户从redis的set集合中移除
                stringRedisTemplate.opsForZSet().remove(key,String.valueOf(userId));
            }
        }
        return null;
    }

    @Override
    public Result queryBlogLikes(Long id) {
        // 1.查询top5的点赞用户 zrange key 0 4
        String key = RedisConstants.BLOG_LIKED_KEY+id;
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        if(top5 == null || top5.isEmpty()){
            return Result.ok(Collections.emptyList());
        }
        // 2.解析出其中的用户id
        List<Long> ids = top5.stream().map(Long::valueOf).collect(Collectors.toList());
        String idsStr = StrUtil.join(",", ids);
        // 3.根据id查询用户 where id in (5,1) order by field(id,5,1)
        List<UserDTO> userDTO = userService.query()
                .in("id",ids).last("order by field(id,"+idsStr+")").list()
                .stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());
        return Result.ok(userDTO);
    }

    @Override
    public Result saveBlog(Blog blog) {
        // 1.获取登录用户
        UserDTO user = UserHolder.getUser();
        blog.setUserId(user.getId());
        // 2.保存探店博文
        boolean isSuccess = save(blog);
        if(!isSuccess){
            return Result.fail("新增笔记失败");
        }
        // 3.查询笔记所有者的所有粉丝
        List<Follow> follows = followService.query().eq("follow_user_id", user.getId()).list();
        // 4.推送笔记id给所有粉丝
        for (Follow follow : follows) {
            // 4.1获取粉丝id
            Long userId = follow.getUserId();
            // 4.2推送
            String key = RedisConstants.FEED_KEY+userId;
            stringRedisTemplate.opsForZSet().add(key,blog.getId().toString(),System.currentTimeMillis());
        }
        // 5返回id
        return Result.ok(blog.getId());
    }

    @Override
    public Result queryBlogOfFollow(Long max, Integer offset) {
        // 1.获取当前用户
        Long userId = UserHolder.getUser().getId();
        // 2.查询收件箱 zrevrangebyscore key max min limit offset count
        String key = RedisConstants.FEED_KEY+userId;
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet()
                .reverseRangeByScoreWithScores(key, 0, max, offset, 2);
        // 3.非空判断
        if(typedTuples == null || typedTuples.isEmpty()){
            return Result.ok();
        }
        // 4.解析数据：blogId、minTime（时间戳）、offset
        List<Long> ids = new ArrayList<>(typedTuples.size());
        long minTime = 0;
        int os = 1;
        for (ZSetOperations.TypedTuple<String> typedTuple : typedTuples) {
            // 4.1获取id
            ids.add(Long.valueOf(typedTuple.getValue()));
            // 4.2获取分数（时间戳）
            long time = typedTuple.getScore().longValue();
            if(time == minTime){
                os++;
            }else {
                minTime = time;
                os = 1;
            }
        }
        // 5.根据id查询blog
        String idStr = StrUtil.join(",", ids);
        List<Blog> blogs = query().in("id", ids).last("order by field(id," + idStr + ")").list();
        for (Blog blog : blogs) {
            // 查询blog有关的用户
            queryBlogUser(blog);
            // 查询blog是否被点赞
            isBlogLiked(blog);
        }
        // 6.封装返回
        ScrollResult result = new ScrollResult();
        result.setList(blogs);
        result.setOffset(os);
        result.setMinTime(minTime);
        return Result.ok(result);
    }

    private void queryBlogUser(Blog blog) {
        Long userId = blog.getUserId();
        User user = userService.getById(userId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
    }
}
